Thread guide



p 21, 1954 GA. HUNTER 2,689,694

THREAD GUIDE Filed Nov. 30, 1951 INVENTOR.

GEIORGE ADAMSON HUN Tn .BY

ATTORNEY.

Patented Sept. 21, 1954 George Adamson Hunter Chattanooga. Tenn assignorto E. I. du Pont de Nemours and Company, Wilmington, Del., a corporationof Delaware Application November 30, 1951, Serial No. 259,086

2 Claims. 1

This invention relates to the winding of threads, and more particularlyto reciprocating thread guides for use therein.

Reciprocating thread guides are used in winding straight sided cakes.When winding such cakes at high speeds it is necessary for the guides toreciprocate at high frequencies in order to obtain good bobbinformation. The textile industry, however, has long been restricted toguides which reciprocate rather slowly and has therefore not been ableto attain the high winding speeds which the other parts of the windingequipment are capable of withstanding.

High frequency reciprocation of these thread guides has not beenpractical previously because it involves an extremely rapid reversal inthe direction of the kinetic energy of the guide at the points of strokereversal. This rapid change in the direction of the kinetic energyproduces extremely high momentary stresses in the guides andcam-followers which, after a few hundred cycles at high speed, causesordinary guides and/or followers to fall through fatigue. Attempts toovercome this fatigue deficiency of common fabricating materials, suchas steel, steel alloys, brasses, bronzes and the like, by the use ofmassive guides necessitates an excessive power input and, in addition,the large mass of the guide places undue stress on the cam-followerswhich causes excessive wear and breakage. A further difficultyencountered at high winding speeds is that the high thread velocityresults in an unexpectedly severe wear on guide surfaces, especiallywhen winding highly delustered threads.

It is an object of this invention to provide a thread guide whichcombines light weight, high strength and fatigue resistance. It is afurther object of this invention to provide a reciprocating thread guidewhich is resistant to mechanical wear where it slides over the guidebars. It is a still further object of this invention to provide aunitary reciprocating thread guide whose thread guiding and threadcontacting surfaces are extremely resistant to wear even when winding ahighly delustered synthetic filament or yarn.

Other objects will become apparent from the following description andclaims.

The objects of this invention are accomplished by forming the main bodyof the reciprocating thread guide of nylon, providing a thread-guidingslot faced with a fused, hard, mineral material, and providingwearresistant surfaces on other portions of the guide which contact thethread during string-up. The invention will be more readily understoodby reference to the drawing, which illustrates preferred embodiments ofshown in Figure 1, in order to show the con-- the thread guide.

Figure 1 is an end view of a thread guide and associatedbobbin windingmechanism,

Figure 2 is an enlargement of the thread guide struction more clearly,

Figure 3 is a cross-section of one embodiment of thread guide inaccordance with this invention, taken on the line 33 of Figure 2,

Figure 4 is a modified form of the embodiment of the invention shown inFigure 3.

Referring to Figure 1, a thread or yarn I 0 passes downward throughguiding portion ll of the thread guide and is Wound into a package l2about bobbin I3, which is rotatably supported on shaft 14. The bobbin isrotated by frictional contact with a motor-driven drive roll [5. Thethread guide is slidably supported on horizontal rod it; by sleevebearing l! integrally molded into the guide. Above bearing I1 is anadditional bearing l8 which slides on guide bar l9. Nylon is anadmirable material for these bearing surfaces because of its long life,resistance to deformation and fatigue, and light weight. It is highlyresistant to wear as a bearing material and the "bearings need only aninitial light oiling, so that one source of yarn contamination andsoiling is eliminated.

The righthand projection 20 of the thread guide contains a hole intowhich the end of cam-follower 2! is fitted. A motor-driven cam shaft 22is provided with a continuous helical groove like thegrooves on thebarrel of an automatic Yankee screw driver. The cam-follower fits intoand follows this groove to provide a reciprocating motion to the threadguide.

Referring to Figure 3, the thread-guiding surfaces comprise slot 25 andleading edges 26. These are surfaces which must be made resistant towear produced by the thread in order to provide the guide with asuitably long life. One manner in which this may be accomplished is toforce pins 2'! of a fused, hard, mineralmaterial into holes 28 drilledor molded into the guide body at the base of the slot so as to align thepins with the slot edges. These pins are a force fit in these holes suchthat the resilient nylon body holds them firmly. These pins contact thethread during the entire winding of the package and should be highlywear-resistant. A good material has been found to be Alsimag, a fusedtitanium di-' oxide supplied by the American Lava Company. Othersuitable materials include fused silica, titania, zirconia, alumina andtheir comounds, e. g.,

porcelain and glass. The leading edges 26, which contact the thread onlyduring string-up, are plated with a layer of hard wear-resistant metal,e. g., nickel, which is then polished smooth. Additionally, the platingis carried over the ends of the pins 21 to provide added insuranceagainst the pins slipping out of place, to prevent breakage of the pinsby anchoring the outer end, and to present a smooth surface forfacilitating the automatic string-up feature described below.

Alternatively, as shown in Figure 4, these wearresistant surfaces may beprovided by a chromeplated or wear-resistant steel alloy wire 30 covingedges 26, and also serving as means for holding hollow mineral pins 3|in the guide slot. Other methods for holding wear-resistant surfaces inplace will be readily apparent to one skilled in the art.-

In Figure l is shown the normal thread line running through the guideslot. At the stringup, the thread is brought down on one side of theguide and wrapped around the bobbin to start the winding operation.Then, as the thread guide reciprocates, the thread automatically ridesover the rounded edge and falls into the slot in its normal runningposition.

For convenience, the invention will be described in terms of a threadwinding device in which the mode of reciprocation is by means of arelatively small diameter cam shaft containing a continuous helicalgroove similar to the groove on the barrel of an automatic Yankee screwdriver. The cam-follower protruding from the hole in the projection 20of the thread guide must have a flat tapered end to make thecam-follower run in the given groove. Otherwise, at the crossovers oftwo slots it could inadvertently get into the wrong groove and go in thewrong direction. At the ends of the traverse stroke, this fiat taperedcam-follower (sometimes called a boat-tail cam-follower) has to rotatethrough the angle prescribed by the slot reversals. Consequently, thecam-follower must be a reasonably loose fit in the hole of thereciprocating thread guide. Due to this factor, light strong metals suchas aluminum, magnesium, or aluminum-magnesium alloys cannot be used as afabrication material for these guides, because of a peening actionbetween the cam-follower and the side walls of the hole which quicklydestroys the usefulness of the thread guide, and because the ductilityof these metals and alloys produces flaring of the end portions of theelongated cylindrical bores which serve as bearing surfaces when theforce couples induced at the reversal points act upon them.

Actually the thread guides of this invention are advantageous with anygrooved cam shaft, whether the groove crosses itself as described aboveor whether the groove has no cross-overs. When the groove has nocross-overs it is normal practice to make the cam-follower an integralpart of the guide (e. g., by making the follower stem a press fit or athreaded fit in the hole of projection 20) and to provide a roller onthe follower end rather than the boat-tail described above.

Additionally, the thread guide of this invention can be used with anyreciprocating guide bar, however actuated. Again, in this instance, itis the usual custom to make the connecting link between the guide andthe bar an integral part of the guide as described above. Thusit can beseen that these methods of construction eliminate the peening actionbetweenthe camfollower and the side walls of the hole in projection 20,but they do not eliminate the equally destructive forces which flare theend portions of the elongated cylindrical bores serving as the bearingsurfaces when these guides are made of the light and strong yet ductilemetals and alloys of aluminum and magnesium.

The molded nylon thread guides of this invention can be operated up to800 or 1,000 cycles per minute, or even more, without failing by fatigueor by damage to the guide or through wear or deformation of the bearingsurfaces. Reciprocating thread guides made of steel usually fail in therange of 200 to 400 cycles per minute. Hence, by the use of the guidesof this invention at 800 cycles per minute, instead of at the customary200 cycles per minute for the guides of the prior art, it is possible toincrease the thread wind-up speed four-fold.

Since many different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof, it is to be understood thatthe invention is not limited by the specific illustrations except to theextent defined in the following claims.

What is claimed is:

l. A reciprocating thread guide comprising in combination a main body ofnylon and a threadguiding slot formed by parallel pins of a fused, hard,mineral material and surfaces for guiding a thread into said slot duringstring-up, said surfaces being provided with wear-resistant inserts.

2. A reciprocating thread guide comprising in combination a main body ofnylon and a threadguiding slot formed by parallel pins of a fusible,hard, mineral material and surfaces for guiding a thread into said slotduring string-up, said surfaces being formed of a wear-resistantmaterial.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,912,256 Coradi May 30, 1933 2,246,086 Austin June 17, 19412,298,34 Childs Oct. 13, 1942 2,299,344 Perry Oct. 20, 1 2,434,227 RoweJan. 6, 1948 FOREIGN PATENTS Number Country Date 472,081 Great BritainSept. 16, 1937 410,180 Italy Mar. 25, 1945 OTHER REFERENCES ModernPlastics, Injection Molding of Nylon, pages -120 and 166, Akin &Teagarden.

Product Engineering, July 1950, Nylon in Bearings and Gears Wall, pages102-107.

